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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2024

2023

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Abstract

There is a stable growth in aquaculture production to avoid seafood scarcity. The usage of eco-friendly feed additives is not only associated with aquatic animal health but also reduces the risk of deleterious effects to the environment and consumers. Aquaculture researchers are seeking dietary solutions to improve the growth performance and yield of target organisms. A wide range of naturally derived compounds such as probiotics, prebiotics, synbiotics, complex carbohydrates, nutritional factors, herbs, hormones, vitamins, and cytokines was utilized as immunostimulants in aquaculture. The use of polysaccharides derived from natural resources, such as alginate, agar, laminarin, carrageenan, fucoidan, chitin, and chitosan, as supplementary feed in aquaculture species has been reported. Polysaccharides are prebiotic substances which are enhancing the immunity, disease resistance and growth of aquatic animals. Further, chitin (CT), chitosan (CTS) and chitooligosaccharides (COS) were recognized for their biodegradable properties and unique biological functions. The dietary effects of CT, CTS and COS at different inclusion levels on growth performance, immune response and gut microbiota in aquaculture species has been reviewed. The safety regulations, challenges and future outlooks of CT, CTS and COS in aquatic animals have been discussed in this review.

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Arctic ecosystems are increasingly exposed to extreme climatic events throughout the year, which can affect species performance. Cryptogams (bryophytes and lichens) provide important ecosystem services in polar ecosystems but may be physiologically affected or killed by extreme events. Through field and laboratory manipulations, we compared physiological responses of seven dominant sub-Arctic cryptogams (three bryophytes, four lichens) to single events and factorial combinations of mid-winter heatwave (6°C for 7 days), re-freezing, snow removal and summer nitrogen addition. We aimed to identify which mosses and lichens are vulnerable to these abiotic extremes and if combinations would exacerbate physiological responses. Combinations of extremes resulted in stronger species responses but included idiosyncratic species-specific responses. Species that remained dormant during winter (March), irrespective of extremes, showed little physiological response during summer (August). However, winter physiological activity, and response to winter extremes, was not consistently associated with summer physiological impacts. Winter extremes affect cryptogam physiology, but summer responses appear mild, and lichens affect the photobiont more than the mycobiont. Accounting for Arctic cryptogam response to multiple climatic extremes in ecosystem functioning and modelling will require a better understanding of their winter eco-physiology and repair capabilities.

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Currently global seaweed industries are facing issue with availability of raw material for processing of carrageenan due to low growth of current planting material. Use of biostimulants in seaweed cultivation is recently paid more attention due to their proven biostimulatory effect, of which, Ascophyllum marine plant extract powder (AMPEP) is a well proven biostimulant to improve the growth and quality of Kappaphycus alvarezii biomass. Hence, 500 kg of AMPEP was purchased and studied its impact on the commercial farming of K. alvarezii from April 2018 to January 2022 in India. Vegetative propagule of K. alvarezii were dipped in an AMPEP with concentration range of: 0.025, 0.05, 0.10, 0.15, 0.20 and 0.25 % for 30, 60, 90 and 120 min. Before out-planting on rafts in shallow coastal water and found that K. alvarezii responded well to a 0.1 % solution with dipping time of 60 min. The percentage of average daily growth rate (ADGR%) of AMPEP-treated plant in a 45 d grow out period was 3.50 ± 0.50 % vs a control of 1.75 ± 0.25 % for the summer and pre-monsoon months (p < 0.05) but no statistically significant differences between the treated and control plants were found during the rainy and winter seasons. Treated plants were found with low incidence of epiphytes, and disease as compared to control plants. The general appearance and health of treated Kappaphycus was good with significant differences in the yield and quality of semi-refined carrageenan (SRC) and dry weed quality (p < 0.05). The cost of AMPEP for producing of additional 1 kg of dry Kappaphycus was 0.066USD. Results of the present study is very encouraging and AMPEP can be used for the production of K. alvarezii biomass for industrial and biorefinery processing as it has been witnessed that there was 16.66 % increase in biomass production in 2021in India.

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Regeneration of polyploidy from young thallus segments of Kappaphycus alvarezii was optimized for genetic improvement. Kappaphycus thallus segment cultured on sterile sea water supplemented with various combinations of Indole acetic acid, Kinetin and Acardian Marine Plant Extract Powder revealed differential response on callus proliferation and development of new thallus. Presence of Acardian Marine Plant Extract Powder (3 mg/l) in combination with Indole acetic acid and Kinetin (0.01 mg/l each) had induced the longest emerging thallus. Exposure of thallus to colchicine at 0.01% with above combination was optimal to induce high frequency regeneration of polyploidy mostly from the meristematic cells. Anatomical study of colchicine induced polyploidy revealed larger cortical cells with irregular thickening of epidermal layer. Phase contrast and Scanning Electron Microscopic study revealed increase in cell size in cortical region with significantly larger number of spherical shaped carrageenan globules in colchicine induced polyploidy than normal thallus. Single cells isolated using enzymatic treatments from colchicine induced polyploidy, shown chromosome number with a ploidy status of 4n ≈ 40. Whereas in normal thallus, only half the number of chromosomes (2n ≈ 20) were observed. Polyploidy were successfully acclimatized gradually using raft method for further evaluation. This is the first report reveals the induction and regeneration of polyploidy in Kappaphycus. The possible application of this finding in genetic improvement of Kappaphycus is discussed.

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The present investigation is aimed at developing films using biomass of seaweed Kappaphycus alvarezii blended with natural additives both without glycerol (K) and with glycerol (KG) and to use the same in enhancement of shelf life of tomatoes. The natural additives used were Azadirachta indica oil (K1), A. indica leaves extract (K2), Citrus limon leaves extract (K3), A. indica gum (K4), Prunus amygdalus gum (K5), Moringa indica gum (K6) and the extract and oil of A. indica leaves (K7). The result showed that the moisture content ranged from 10.3 ± 1.2–19.9 ± 0.4%, thickness 0.01–0.10 mm, and swelling index above 45% in all the prepared films. The tensile strength and transparency were higher for K6, KG6, K and KG respectively. KG6 and K3 films showed maximum phenolic content, antioxidant and antimicrobial activity. The promising results of current investigation proved the suitability of the film in enhancing the shelf life of tomatoes to 14 days at room temperature.

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Processing of 1000 kg of fresh Kappaphycus alvarezii yielded 25 kg salt. The optical microscopy revealed non-crystalline nature, absence of geometrical pattern; while squircle aggregates with ruffled surface were evident in SEM. Caenorhabditis elegans assay confirmed its non-toxicity; while absence of Salmonella and pesticides make it safe for human consumption. Among the macro elements, ‘K' content was highest (3792.74 ± 541.23 mg 100 g−1) and ‘Ca’ was lowest (7.01 ± 1.32 mg 100 g−1); whereas among micro element ‘Fe’ was highest (6.52 ± 1.40 mg 100 g−1) and ‘Ni’ lowest (0.14 ± 0.01 mg 100 g−1). Chromium (11.5 μg g−1) was lower than a permissible daily dose, while other heavy metals (Mo, Cu, Co, Zn, As, Cd, Hg, and Pb) were below detectable level. PXRD revealed that it has only KCl Form I. The study suggested potential economic utility of seaweed salt under the framework of waste to wealth.

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This trial aimed to assess the growth performance of trout (Oncorhynchus mykiss) fed novel formulations, evaluate fish welfare status, and determine flesh quality as part of the evaluation of sustainable feeds. A control diet containing fish meal and soy products (CTRL) was compared to: a diet with processed animal proteins (PAP); a diet without PAP (NoPAP); a PAP diet lower in protein (PAP−); and a NoPAP diet higher in protein (NoPAP+). Groups of 50 fish, weighing 58.84 ± 1.39 g (IBW), were allocated to 20 tanks and fed with formulated diets ad libitum over 91 days. Better growth performance was observed after the experiment in fish fed the NoPAP+ diet when compared to other diets. Protein retention was higher in CTRL diets than in PAP and PAP− diets. Protein and phosphorous digestibility were lower in fish fed PAP− diet. Diets did not influence the texture analysis. However, sensory analysis revealed higher acceptance for fish fed the NoPAP diet when compared to the PAP diet. Lysozyme was higher in the NoPAP diet than in other treatments. In addition, long-term predictions using FEEDNETICSTM software suggest some of these alternative formulations may be economically sustainable. Overall, these results support the hypothesis that the new formulations are viable options for trout farming.

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Background and terms of reference Farmed Atlantic salmon (Salmo salar) that escape into the wild could interbreed with native fish, posing a potential risk to the genetic diversity of wild Atlantic salmon populations. The Atlantic salmon in aquaculture are diploid, meaning the fish has two sets of chromosomes. To mitigate the genetic impact on wild populations, the concept of producing sterile triploid farmed Atlantic salmon has been suggested as a solution. However, it is important to ensure that the utilization of triploids in commercial farming aligns with the regulations set forth in the Norwegian Animal Welfare Act. The Norwegian Food Safety Authority (NFSA) requested the Norwegian Scientific Committee for Food and Environment (VKM) to do an assessment about health- and welfare consequences in triploid Atlantic salmon under commercial farming conditions, as compared to diploid counterparts. VKM was also requested to describe the underlying physiological mechanisms concerning consequences of triploidy as well as address potential measures to reduce the negative impacts on the health and welfare of the fish. Methods A working group consisting of members with expertise in salmonid biology, aquaculture systems, veterinary medicine, fish health and welfare, virology, bacteriology, parasitology, breeding and genetics has drafted this opinion. To answer the Terms of Reference as mandated by the NFSA, the authors addressed fish health and welfare as a unified concept in this report. Two external experts have reviewed and provided their opinion before it was assessed and approved by the VKM’s Panel on Animal Health and welfare. The literature used in this work was peer-reviewed studies retrieved from a search in four databases as well as non peer-reviewed reports. Selection of studies was conducted independently by two members in the working group and based on predefined inclusion and exclusion criteria. Conclusions Under commercial farming conditions, triploid Atlantic salmon are often found to have lower standards of health and welfare compared to diploids. For example, field and experimental studies have found triploids to be more prone to skeletal and heart deformities, and cataracts, while field studies suggest that under commercial farming conditions they cope less well with handling and are more susceptible to skin ulcers. However, research has indicated that some of the effects of triploidy can be mitigated through specialized diets or environmental adjustments. There is a noticeable tendency across farm studies and experimental trials for triploid salmon to be equal or larger in size at the end of freshwater phase, but equal or smaller in size at the end of the seawater phase. Most publications conclude that within what is considered the optimal temperature range of diploids, oxygen consumption rate, oxygen binding capacity, and aerobic swimming capacity do not significantly differ between triploid and diploid Atlantic salmon. However, findings from experimental trials suggest a lower optimal temperature range for triploids, and data consistent across studies indicate that triploids possess lower tolerance to hypoxia at elevated temperatures. Triploid Atlantic salmon are less robust to higher water temperatures than diploid, and have other nutritional needs than diploids, especially regarding phosphorus, and histidine. There are few studies on the susceptibility of triploid salmon to infectious agents and diseases. Field observations indicate that triploid fish are more susceptible to primary infectious salmon anaemia (ISA) outbreaks than diploids under commercial farming conditions at the level of the farm, and at cage level within farms that experience an ISA outbreak. A higher susceptibility to the ISA virus would potentially affect not only the health and welfare of the triploid fish at the farm with an outbreak but may potentially spread to other farms. .............